dgecon dgecov dgels dgesv dlange dlansy dpocon dposv dsyev

dpocon() def dpocon ( uplo  , n  , a  , anorm    ) Condition number of a symmetric positive definite matrix Purpose dpocon estimates the reciprocal of the condition number (in the 1-norm) of a real symmetric positive definite matrix using the Cholesky factorization A = U^T*U or A = L*L^T computed by dpotrf. An estimate is obtained for norm(inv(A)), and the reciprocal of the condition number is computed as rcond = 1 / (anorm * norm(inv(A))). Returns (rcond, info) rcond (float): The reciprocal of the condition number of the matrix A, computed as rcond = 1/(anorm * ainvnm), where ainvnm is an estimate of the 1-norm of inv(A) computed in this routine. info (int): = 0: Successful exit = -1: The argument uplo had an illegal value (uplo != 'U' nor 'L') = -2: The argument n had an illegal value (n < 0) = -3: The argument a is invalid. = -4: The argument anorm had an illegal value (anorm < 0) Parameters [in] uplo Specifies whether the factor U or L is stored. = 'U': Upper triangular factor U from the Cholesky factorization A = U^T*U. = 'L': Lower triangular factor L from the Cholesky factorization A = L*L^T. [in] n Order of the matrix A. (n >= 0) (If n = 0, returns rcond = 1) [in] a Numpy ndarray (2-dimensional, float, n x n) The triangular factor U or L from the Cholesky factorization A = U^T*U or A = L*L^T, as computed by dpotrf. [in] anorm The 1-norm (or infinity-norm) of the symmetric matrix A. (anorm >= 0) Reference LAPACK Example Program See example of dposv.